Comparative Evaluation of Organic and Natural Farming Systems on Growth Dynamics and Physiological Performance of Sweet Corn (Zea Mays L. Var saccharata)

Introduction

Agriculture is presently confronted with the challenge of enhancing crop productivity while maintaining environmental sustainability and conserving natural resources. The excessive dependence on synthetic fertilizers and pesticides over the past decades has resulted in several concerns, including soil degradation, declining soil organic matter, reduced microbial diversity, nutrient imbalance, and environmental pollution. Therefore, sustainable agricultural approaches that promote ecological balance, improve soil health, and ensure safe food production have gained significant importance globally (FAO, 2021). Organic farming has emerged as one of the promising alternatives to conventional agriculture by relying on natural inputs such as farmyard manure, compost, vermicompost, green manures, and biofertilizers to maintain soil fertility and crop productivity. Organic production systems enhance soil biological activity, improve nutrient cycling, and contribute to long-term soil fertility. Natural farming is another ecological farming approach aims to minimize production costs while improving soil health and sustainability (NITI Aayog, 2018) [12] . The system utilizes locally prepared biological inputs such as Beejamrutha, Jeevamrutha, botanical extracts, and mulching materials to enhance microbial activity, nutrient availability, and crop resilience. (Subhash et al., 2020) [16] . Sweet corn (Zea mays L. var. saccharata) is an important specialty maize crop cultivated for fresh consumption due to its high nutritional value, taste, and economic importance. Being a short-duration and high-value crop, sweet corn requires adequate nutrient availability throughout the growing period for optimum vegetative growth, photosynthetic efficiency, and yield formation. Growth attributes such as plant height, number of leaves, leaf area index, chlorophyll content, and dry matter accumulation are important indicators of crop establishment and physiological performance. Efficient nutrient management through organic sources can influence these parameters by improving soil physical properties, nutrient availability, and microbial activity. Although organic and natural farming systems share common objectives of reducing chemical inputs and improving ecological sustainability, they differ in nutrient management approaches. The efficiency of nutrient management systems can be assessed through plant growth dynamics and physiological traits, as these parameters directly reflect nutrient uptake, photosynthetic activity, and biomass production. Improved nutrient availability and enhanced soil microbial activity under sustainable farming systems may promote better plant growth, higher dry matter accumulation, and improved physiological efficiency. However, scientific information comparing organic and natural farming systems for their influence on sweet corn growth and physiological performance remains limited. Therefore, the present investigation was undertaken to comparatively evaluate organic and natural farming systems on growth dynamics and physiological performance of sweet corn (Zea mays L. var. saccharata) with the aim of identifying suitable sustainable production practices for enhancing crop growth and promoting environmentally responsible sweet corn cultivation.

Materials and Methods

Experimental site and climate

The field experiment was conducted during three consecutive Rabi seasons (2019-20, 2020-21, and 2021-22) at the Agricultural Research station, Karimnagar, Telangana state, India, located at altitude of 259.2 mean sea level on 18 o 44'31" N latitude and 79 o 09'52" E longitude. The site falls under semi-arid region of Northern Telangana agro-climatic zone characterized by hot and dry weather with mean maximum temperatures ranging between 24.4 -37.2°C and minimum temperatures of 14.1-27.1°C during the cropping period. The annual rainfall of the region is around 953 mm, mostly received during the south west monsoon months whereas irrigation is required for rabi cultivation. The experimental soil was red sandy loam in texture, and low in available nitrogen, medium in phosphorus, and high in potassium. The initial soil chemical characteristics were: pH 7.1, electrical conductivity 0.21 dS m⁻¹, organic carbon 0.46%, available N 255.4 kg ha⁻¹, P₂O₅ 19.8 kg ha⁻¹, and K₂O 312.6 kg ha⁻¹.

Experimental design and treatments

The experiment was laid out in a Randomized Block Design (RBD) with five nutrient management treatments replicated five times. Each plot measured 100 m 2 with appropriate border spacing to minimize nutrient interference. The treatments were as follows: The recommended dose of fertilizers (RDF) for sweet corn was 200:60:50 kg N:P₂O₅:K₂O ha⁻¹. For the organic and INM treatments, nutrient equivalents were computed based on the nutrient content of the respective organic materials.

Crop management

Certified seeds of sweet corn (Zea mays L. var. saccharata) variety Madhuri were sown manually during the second week of October each year at a spacing of 60 × 25 cm. A uniform seed rate of 20 kg ha⁻¹ was used, and the crop was thinned to one plant per hill at 15 days after sowing (DAS). In the organic and INM treatments, farmyard manure and vermicompost were applied one week before sowing and incorporated into the soil. Inorganic fertilizers were applied as per the treatment schedule: one-half of nitrogen and the full dose of phosphorus and half of the dose of potassium were applied as basal, and the remaining nitrogen was top-dressed in two equal splits at 30 and 55 DAS along with half of the dose of potassium at 55 DAS. In natural farming, Ghanajeevamrutam (a mixture of cow dung, cow urine, jaggery, pulse flour, and soil) was applied as basal @ 500 Kg/ha and at every 15-day interval, dhravajeevamrutam is applied as a soil drench. Beejamrut was used for seed treatment, and mulching with crop residues was maintained throughout the crop period.

Irrigation was provided at critical growth stages knee height, tasseling, and grain filling depending on the soil moisture status. Intercultural operations such as thinning, weeding, and earthing up were performed as per standard agronomic practices.

Observations on growth data recording

Observations were recorded from five randomly selected plants in each plot for growth parameters such as plant height, number of leaves per plant, leaf area index (LAI), and dry matter accumulation (DMA) were recorded at 20, 40, 60, and harvest from which physiological parameters as crop growth rate and absolute growth rate were calculated.

Statistical analysis

All recorded data were subjected to analysis of variance (ANOVA) for a randomized block design using the statistical software. Treatment means were compared using the least significant difference (LSD) test at a 5% probability level (p ≤ 0.05). Data across the three years were analyzed both individually and as pooled means to understand the consistency and interaction effects of treatments over seasons.

Results and Discussion

The plant height of maize increased significantly from 20 DAS to harvest under all nutrient management treatments. Significant differences among treatments were observed at 40, 60 DAS and at harvest, indicating the influence of nutrient management practices on crop growth. The Integrated Nutrient Management (INM) resulted in significantly highest pooled plant height throughout the crop growth period, recording 40.6 cm at 20 DAS, 81.8 cm at 40 DAS, 148.7 cm at 60 DAS, and 161.9 cm at harvest. This was closely followed by the inorganic fertilizer treatment, which recorded pooled plant heights of 37.3, 70.8, 136.5, and 151.7 cm, respectively (Table 1). Among the organic-based systems, organic farming resulted in significantly greater plant height than natural farming, with pooled values of 28.0, 50.9, 104. [2] , agree with earlier reports that integrated nutrient management significantly enhances vegetative growth and leaf production in maize and sweet corn by improving nutrient availability and physiological efficiency.

3.3: Leaf area plant -1 and leaf area index (LAI)

Leaf area plant [14] and Ladha et al. (2022) [7] , who reported significantly greater leaf development under integrated nutrient management than under sole organic nutrient application.

The pooled data (Table 5) revealed that nutrient management practices significantly influenced the stalk girth of sweet corn throughout the crop growth period. Differences among treatments became more pronounced as the crop advanced from 20 DAS to harvest. At harvest, INM maintained significantly higher stalk girth (6.78 cm), followed by inorganic fertilization (6.07 cm). Organic farming (5.48 cm) also recorded appreciably higher stalk girth than natural farming (4.86 cm) and control (4.32 cm) which recorded least stalk girth. Similar trend was followed at 20 & 60 DAS. While at 40 DAS, the INM recorded significantly highest stalk girth (5.81 cm) than all treatments. This was followed by inorganic treatment (5.41cm) and organic treatment (4.24 cm). The later was found to be on par with Natural farming (4.05 cm) which was in turn on par with control (3.69 cm). Similar superiority of integrated nutrient management in improving stem diameter has been reported by Kumar et al. (2020) [5] and Singh et al. (2022) [14] , who observed improved nutrient uptake and photosynthetic efficiency under integrated nutrient management which led to higher stem diameter. Greater stalk girth under INM indicates stronger stem development resulting from improved nitrogen availability, better root growth and enhanced translocation of assimilates. Organic farming also improved stalk girth over natural farming owing to gradual nutrient release and improvement in soil biological activity. These findings corroborate those of Mahanta et al. (2021) [9] and Meena et al.

(2020) [10] , who reported enhanced stem growth in maize under integrated nutrient management.

Dry matter accumulation differed significantly among nutrient management practices throughout crop growth (Table 6). The accumulation increased progressively from 20 DAS to harvest, reflecting active biomass production during vegetative and reproductive phases. At 20 DAS, the pooled dry matter accumulation did not differ significantly. While at 40 DAS, biomass accumulation increased sharply under all treatments.

INM produced significantly highest pooled dry matter (110.9 g m⁻²), significantly exceeding inorganic fertilization (70.67 g m⁻²), organic farming (32.54 g m⁻²), natural farming (28.5 g m⁻²) and control (24.0 g m⁻²). Enhanced biomass under INM resulted from improved nutrient uptake, higher leaf area development and increased photosynthetic activity. A similar trend continued at 60 DAS, where INM recorded the highest pooled dry matter production (163.2 g m⁻²), followed by inorganic fertilization (138.4 g m⁻²). Organic farming (70.4 g m⁻²). which accumulated on par biomass with natural farming (59.2 g m⁻²) inturn on par with that of control (49.6 g m⁻²). These observations agree with Jeevabharathi et al., (2020) [3] , who reported that balanced nutrient supply improves radiation interception and dry matter accumulation in maize. At harvest, similarly, significantly maximum pooled dry matter production (298.1 g m⁻²) was observed under INM, followed by inorganic fertilization (230.4 g m⁻²), organic farming (150.0 g m⁻²) which is on par with natural farming (127.3 g m⁻²) and later is in turn on par with control (114.6 g m⁻²). The superiority of INM could be attributed to continuous nutrient availability throughout the crop growth period, resulting in sustained photosynthesis and efficient assimilate partitioning. Organic farming also produced substantially higher biomass along with natural farming due to improved soil organic carbon and microbial activity. These findings are consistent with Ramesh et al. (2021) [13] and Srinivasarao et al. (2022) [15] who reported that integrated nutrient management enhances biomass production and crop productivity through improved soil health and nutrientuse efficiency.

Crop Growth Rate (CGR) differed significantly among nutrient management practices at different crop growth stages during Rabi 2019-20 to 2021-22 (Table 7). (2022) [11] , Kumar et al. (2021) [6] , Singh et al. (2022) [14] and FAO (2023), who observed higher crop growth rates under integrated nutrient management owing to improved nutrient availability and soil health.

Absolute Growth Rate (AGR) increased progressively with crop age and varied significantly among nutrient management practices (Table 8). At 20 DAS, pooled AGR varied from 0.11 to 0.48 g day⁻¹. INM recorded significantly highest AGR (0.48 g day⁻¹), on par with inorganic farming (0.42 g day⁻¹). This was followed by organic farming (0.25 g day⁻¹) which was on par with natural farming (0.14 g day⁻¹) and control (0.11 g day⁻¹). While, At 40 DAS, AGR increased substantially with crop establishment. The pooled AGR was highest under INM (4.85 g day⁻¹), followed by inorganic farming (2.95 g day⁻¹) and organic farming (1.14 g day⁻¹). But Organic farming was in turn on par with natural farming (1.10 g day⁻¹) and the control (0.93 g day⁻¹). Similar trend was followed at 40-60 DAS and 60-harvest stage (Table 8).

Higher AGR under INM could be attributed to sustained nutrient availability throughout the crop growth period, which enhanced photosynthetic efficiency, dry matter accumulation and partitioning of assimilates. Organic farming recorded on par AGR to that of natural farming and control owing to improved soil microbial activity and gradual nutrient release, though the response was relatively slower because of delayed mineralization of organic nutrient sources. These findings corroborate the reports of Mahajan et al. (2019) [8] , Kumar et al. (2021) [6] , Singh et al.

(2022) [14] and Ladha et al. (2022) [7] , who reported that integrated nutrient management enhances crop growth dynamics through improved soil fertility, nutrient use efficiency and biological activity.

Conclusion

The three-year study on INM, Organic, Natural farmig over convetional farming demonstrated that nutrient management practices significantly influenced the growth and physiological performance of sweet corn under the semi-arid conditions of Telangana. Integrated nutrient management significantly recorded the highest plant height, leaf production, leaf area index, stalk girth, dry matter accumulation, crop growth rate and absolute growth rate throughout the crop growth period. The superior performance of INM was primarily due to the synergistic effect of organic and inorganic nutrient sources, which ensured balanced nutrient supply, improved nutrient-use efficiency and enhanced soil biological activity. Inorganic fertilization ranked next in performance, while organic farming showed better growth than natural farming and the control, indicating the positive role of organic nutrient sources in improving soil fertility and crop performance. Natural farming produced comparatively lower growth attributes because of slower nutrient release due to biological nutrient mobilization, although it remained superior to the unfertilized control. Overall, the findings indicate that integrated nutrient management offers the most effective approach for achieving higher productivity while sustaining soil health and environmental quality. Therefore, INM can be recommended as a practical and sustainable nutrient management strategy for sweet corn cultivation in the semi-arid regions of India.

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